| 摘要 |
PURPOSE:To form the titled foam particles of a uniform expansion ratio, by dispersing polyolefin resin particles containing a higher fatty acid salt in water contained in a sealed vessel, heating the dispersion to a predetermined temperature, and discharging it into air. CONSTITUTION:Use is made of particles of a polyolefin resin (e.g., propylene/ ethylene random copolymer) containing 0.4-10wt% 12-22C higher fatty acid metal salt (e.g., aluminum stearate). Namely, in a sealed vessel, 100pts.wt. above polyolefin resin particles are dispersed in about 200-1,000pts.wt. aqueous medium (preferably, a dispersion obtained by adding sodium dodecylbenzenesulfonate to a suspension of a difficulty water-soluble salt formed by mixing an aqueous calcium hydroxide solution with an aqueous phosphoric acid solution). The resulting dispersion is heated (this is accompanied with a pressure increase) to a temperature of the softening point of the resin - (its m.p.+25 deg.C). The resin particles together with the aqueous medium are discharged into air to obtain expanded particles.
|
